Abstract: Provided herein is an aqueous ink, which is excellent in both image density and fixing ability irrespective of the kind of a recording medium even when the volume of an ink droplet is small and has such excellent properties that white stripes are not caused even when high-speed recording is conducted. The aqueous ink comprises at least water, a water-soluble organic solvent, a water-insoluble coloring material, a surfactant and a poor medium for the water-insoluble coloring material and/or a salt. The dynamic surface tension of the aqueous ink at a lifetime of 50 milliseconds determined by a maximum bubble pressure method is higher than 47 mN/m, and the dynamic surface tension at a lifetime of 5,000 milliseconds determined by the maximum bubble pressure method is 38 mN/m or lower.

Abstract: Novel conditions in the physical properties of an ink have been found out to provide an aqueous ink, which can give a high image density and achieve excellent fixing ability. The aqueous ink comprises at least water, a water-soluble organic solvent, a surfactant and a coloring material, wherein the dynamic surface tension at a lifetime of 50 milliseconds as determined by a maximum bubble pressure method is 49 mN/m or more, and the dynamic surface tension at a lifetime of 5,000 milliseconds as determined by the maximum bubble pressure method is 38 mN/m or less.

Abstract: To relate to a head liquid which is supplied to efficiently remove ink residues and the like which are attached to the surface of an inkjet head provided with ejection openings through which an ink containing a color material is ejected. In a case where a nonvolatile solvent such as glycerin is used as the head liquid, the nonvolatile solvent absorbs moisture, and thereby an extremely large change in mass is exhibited. As a result, the above supply amount is varied. To solve the problem, it was found that the previous mixing of water with the nonvolatile solvent can provide a smaller change in mass than that in a case where the nonvolatile solvent by itself is caused to absorb moisture. Accordingly, a mixture prepared by mixing the nonvolatile solvent and water in an appropriate predetermined ratio is used as a head liquid.

Abstract: A method of a cleaning of an ejection face by supplying a head liquid on the face of an inkjet head provided with ink ejection openings and then by performing a wiping operation. Sufficient cleaning is achieved by appropriately specifying relative relationships among the surface tensions of the face, the ink and the head liquid, and by efficiently and surely removing an ink residue from the face. By supplying the head liquid to the ink residue on the face, both are mixed with each other, and thereby the ink residue is incorporated into the head liquid. In this respect, by using the ink and the head liquid both having a surface tension higher than that of the face, a wetting of a dissolved matter of the ink residue with respect to the face is reduced, and the dissolved matter of the ink residue is smoothly moved by the wiping operation.

Abstract: Disclosed is an aqueous ink comprising at least water, a plurality of water-soluble organic solvents and a coloring material. The coloring material is a pigment, and, it contains a pigment particle having at least one ionic group bonded to a surface of the pigment particle directly or via another atomic group. The plurality of water-soluble organic solvents have a good medium or good mediums for the pigment and a poor medium or poor mediums for the pigment. The poor medium does not solvate perfectly or substantially the pigment. The ionic group undergoes perfectly or substantially no ionic dissociation in the poor medium. Also, among the respective Ka values of the plurality of water-soluble organic solvents as determined by the Bristow method, the Ka value of the poor medium is maximum.

Abstract: A cyan ink applicable to an ink set has plurality of aqueous inks each containing at least: water; a water-insoluble coloring material; and plurality of water-soluble organic solvents including a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material. A ratio of a poor medium to a good medium in the cyan ink is in a specific range. A water-soluble organic solvent showing the maximum Ka value out of respective Ka values of the plurality of water-soluble organic solvents is the poor medium. A ratio of a poor medium to a good medium in an arbitrary aqueous ink in the ink set except the cyan ink and the ratio of the poor medium to the good medium in the cyan ink satisfy a specific relationship.

Abstract: An aqueous ink comprising at least water, a water-soluble organic solvent and a colorant. The colorant comprises a pigment containing a pigment particle having at least one ionic group bonded to a surface of the pigment particle directly or via another atomic group. The organic solvent undergoes completely or substantially no solvation with the pigment and the ionic group of the pigment particle undergoes completely or substantially no ion dissociation in the organic solvent.

Abstract: Provided are an aqueous ink containing: water; multiple water-soluble organic solvents; and a dispersible colorant, the aqueous ink containing a good medium with respect to the dispersible colorant and a bad medium with respect to the dispersible colorant as the water-soluble organic solvents, in which: the dispersible colorant is a dispersible colorant having a colorant and chargeable resin pseudo fine particles each of which is smaller than the colorant in which the colorant and the chargeable resin pseudo fine particles fix to each other; and when a total amount of the good medium in the ink (mass %) is denoted by A and a total amount of the bad medium in the ink (mass %) is denoted by B, A:B is in the range of 10:5 to 10:30.

Abstract: In an inkjet printing apparatus, when a printing is performed by generating the reacting so that, on the printing sheet, permeation of an ink solvent is delayed to prevent that the fixing time is prolonged thereby. A printing sheet is sucked by the comparatively weak suction force in a degree in which the sheet is tightly contacted with the pore of the platen. Hereby, insolubilized or coagulated coloring matters and the ink solvent except the reactive radical component or water on the sheet are sucked together into the sheet, and then the forcible permeation condition is formed. As a result, the fixing time is shorter than in a case where there is no suction, and the fixing by the reactive system ink-set can be accelerated.

Abstract: Provided is a cyan ink applicable to an ink set having four kinds of aqueous inks composed of the cyan ink, a magenta ink, a yellow ink, and a black ink each containing water; a water-insoluble coloring material; and plurality of water-soluble organic solvents including a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material. The content of the water-insoluble coloring material in the cyan ink is in a specific range, and the ratio B1/A1 between the good medium and the poor medium is also in a specific range. A water-soluble organic solvent showing the maximum Ka value out of respective Ka values of the plurality of water-soluble organic solvents is the poor medium. The ratio A/B between the good medium and the poor medium in an arbitrary aqueous ink in the ink set except the cyan ink and B1/A1 satisfy a specific relationship.

Abstract: A recording method is provided which enables formation of an image with high image density and low graininess. The recording is conducted by using a recording method using a first aqueous ink for higher-density recording and a second aqueous ink for lower-density recording, characterized in that the first aqueous ink comprises at least water, a water-insoluble coloring material, and plurality of water-soluble organic solvents, the plurality of water-soluble organic solvents including a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material, the ratio B/A in the second aqueous ink being less than the ratio B/A the first aqueous ink, where A denotes the total content (mass %) of good medium based on the total mass of the aqueous ink and B denotes the total content (mass %) of poor medium based on the total mass of the aqueous ink; and the second aqueous ink has the same hue as the first aqueous ink.

Abstract: An aqueous ink comprises water, a water-insoluble coloring material, and plurality of water-soluble organic solvents and the plurality of water-soluble organic solvents including a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material. The ratio of the content of the poor medium and the content of the good medium is in a specific range. A water-soluble organic solvent showing the maximum Ka value out of respective Ka values of the plurality of water-soluble organic solvents is the poor medium. When the aqueous ink is in contact with a specific reaction liquid, the dissolution state or dispersed state of the water-insoluble coloring material in the ink is made unstable. As a result, an image which has a sufficiently large area factor even with a small amount of ink droplets and is excellent in image density, bleeding resistance, and fixability can be obtained.

Abstract: A cyan ink applicable to an ink set has plurality of aqueous inks each containing at least: water; a water-insoluble coloring material; and plurality of water-soluble organic solvents including a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material. A ratio of a poor medium to a good medium in the cyan ink is in a specific range. A water-soluble organic solvent showing the maximum Ka value out of respective Ka values of the plurality of water-soluble organic solvents is the poor medium. A ratio of a poor medium to a good medium in an arbitrary aqueous ink in the ink set except the cyan ink and the ratio of the poor medium to the good medium in the cyan ink satisfy a specific relationship.

Abstract: The present invention aims to provide an ink which has a sufficiently large area factor even in a small ink droplet quantity and can obtain images having a high image density, and further has a superior storage stability. According to the present invention, a cyan ink is provided which is used in an ink set having four kinds of aqueous inks consisting of a cyan ink, a magenta ink, a yellow ink and a black ink in which each ink comprises at least water, a water-insoluble coloring material, and a plurality of water-soluble organic solvents having a good medium or good mediums for the water-insoluble coloring material and a poor medium or poor mediums for the water-insoluble coloring material, wherein, the ratio B1/A1 is from 0.5 or more to 3.

Abstract: The present invention relates to an aqueous ink, particularly an aqueous ink suitable for ink jet recording. The ink is an aqueous ink comprising a modified pigment having organic groups chemically attached to the surface of a particle of the pigment and an aqueous medium which is a dispersant of the pigment, wherein the above-described organic group includes a reaction product of a functional group chemically attached to the surface of the pigment directly or via another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer.

Abstract: An ink set, which is an ink set (A) obtained by combining a plurality of aqueous inks (a) and is used together with an aqueous ink (B) containing a water-insoluble coloring material, wherein respective aqueous inks constituting the ink set (A) contain at least one water-soluble organic solvent serving as a poor solvent for the water-insoluble coloring material constituting the aqueous ink (B), and among the water-soluble organic solvents which are respectively contained in the aqueous ink (a) and serve as a poor solvent, at least one water-soluble organic solvent has a vapor pressure at 20° C. lower than the vapor pressure of water at 20° C. It is possible to obtain an image in which occurrence of the bleeding at the boundaries between different color regions has been suppressed in the case where a full-color image in which the respective color-regions are situated adjacently to one another is formed.

Abstract: The present invention relates to an aqueous ink, particularly an aqueous ink suitable for ink jet recording. The ink is an aqueous ink comprising a modified pigment having organic groups chemically attached to the surface of a particle of the pigment and an aqueous medium which is a dispersant of the pigment, wherein the above-described organic group includes a reaction product of a functional group chemically attached to the surface of the pigment directly or via another atomic group with a copolymer of an ionic monomer and a hydrophobic monomer.

Abstract: A surface reforming method capable of efficiently carrying out a sustainable, even reforming treatment on a prescribed surface part of an element, a surface treatment liquid to be employed for the above-described method, and an element having a reformed surface treated by the above-described method. A part of the surface of an element is subjected to the reforming treatment by providing the object surface with a polymer, which is different from a constituent material of the objet surface and comprises a first part having a functional group and a second part having an interfacial energy different from that of the functional group and approximately equal to the surface energy of the object surface and orienting the second part of the polymer toward the object surface and orienting the first part in a direction different from the object surface.

Abstract: A surface reforming method capable of efficiently carrying out a sustainable, even reforming treatment on a prescribed surface part of an element, a surface treatment liquid to be employed for the above-described method, and an element having a reformed surface treated by the above-described method. A part of the surface of an element is subjected to the reforming treatment by providing the object surface with a polymer, which is different from a constituent material of the objet surface and comprises a first part having a functional group and a second part having an interfacial energy different from that of the functional group and approximately equal to the surface energy of the object surface and orienting the second part of the polymer toward the object surface and orienting the first part in a direction different from the object surface.

Abstract: In an inkjet printing apparatus, when a printing is performed by generating the reacting so that, on the printing sheet, permeation of an ink solvent is delayed to prevent that the fixing time is prolonged thereby. A printing sheet is sucked by the comparatively weak suction force in a degree in which the sheet is tightly contacted with the pore of the platen. Hereby, insolubilized or coagulated coloring matters and the ink solvent except the reactive radical component or water on the sheet are sucked together into the sheet, and then the forcible permeation condition is formed. As a result, the fixing time is shorter than in a case where there is no suction, and the fixing by the reactive system ink-set can be accelerated.